I think if it was the series finale, then they both would have been in the cage. But what we were given suited the series, imo.

The only thing I disagree with is that Sam is still Lucifer. I think that story is done. Maybe I'm wrong. The writers have said repeatedly the storyline was ending this season no matter what. But they tend to lie. I don't know what we're supposed to make of Sam there at the end.